Note: Keir just drop non-PAE support in the 3.3 branch, so we are stuck
with 3.0-3.2 until we implement PAE

In addition to the list: supporting partitions: in the configuration
file, one can say "hda1" instead of "hda", which means that we are
supposed to create an hd0s1 device instead of just hd0. This is done by
interpreting the vbd number as follows: